I know and cannot deny the enormous effort of OCE. I tried to develop a simpler parametric 2d cad once for almost two years, but couldn't keep up with the complexity before getting myself /something/ I could use.

This is why I keep trying. FreeCAD is the closest package we got to a decent CAD in an OSS package, and I cannot wait to avoid using closed software in my designs.

But I'm just stating facts here: I couldn't follow the tutorial without incurring in crashes. I similarly tried CadQuery, but incurred with mostly the same issues.

But like I said, the issues are also on the UI, not just on the OCE engine.

UNDO management is often completely broken. Undoing line properties for instance used to only partially revert line properties, but revert previous geometry changes as a side effect. I got crashes just by toggling snapping states (even before hovering over the geometry that would cause some actual computation to be done). I thought I could help on those issues, but the build process involving OCE is time consuming and requires some non-trivial time investment before you can become an effective contributor (as for most large projects - cannot blame anyone here).

I occasionally use FreeCAD also as a simple 2d (non-parametric) CAD package. Still very frustrating. You would think we had more options for 2d drafting, but not really. I do not consider qcad/librecad to be real CAD packages. They're like toys in my eyes. I used inkscape (yes...) with greater results.